sata_mv: remove bogus nsect restriction

Remove unneeded nsect restriction from GenII NCQ path,
and improve comments to explain why this is not a problem.

Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index 6809628..874b60b 100644 (file)
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -349,8 +349,6 @@ enum {
 
        EDMA_HALTCOND_OFS       = 0x60,         /* GenIIe halt conditions */
 
-       GEN_II_NCQ_MAX_SECTORS  = 256,          /* max sects/io on Gen2 w/NCQ */
-
        /* Host private flags (hp_flags) */
        MV_HP_FLAG_MSI          = (1 << 0),
        MV_HP_ERRATA_50XXB0     = (1 << 1),
@@ -1093,20 +1091,12 @@ static void mv6_dev_config(struct ata_device *adev)
         *
         * Gen-II does not support NCQ over a port multiplier
         *  (no FIS-based switching).
-        *
-        * We don't have hob_nsect when doing NCQ commands on Gen-II.
-        * See mv_qc_prep() for more info.
         */
        if (adev->flags & ATA_DFLAG_NCQ) {
                if (sata_pmp_attached(adev->link->ap)) {
                        adev->flags &= ~ATA_DFLAG_NCQ;
                        ata_dev_printk(adev, KERN_INFO,
                                "NCQ disabled for command-based switching\n");
-               } else if (adev->max_sectors > GEN_II_NCQ_MAX_SECTORS) {
-                       adev->max_sectors = GEN_II_NCQ_MAX_SECTORS;
-                       ata_dev_printk(adev, KERN_INFO,
-                               "max_sectors limited to %u for NCQ\n",
-                               adev->max_sectors);
                }
        }
 }
@@ -1444,7 +1434,8 @@ static void mv_qc_prep(struct ata_queued_cmd *qc)
         * only 11 bytes...so we must pick and choose required
         * registers based on the command.  So, we drop feature and
         * hob_feature for [RW] DMA commands, but they are needed for
-        * NCQ.  NCQ will drop hob_nsect.
+        * NCQ.  NCQ will drop hob_nsect, which is not needed there
+        * (nsect is used only for the tag; feat/hob_feat hold true nsect).
         */
        switch (tf->command) {
        case ATA_CMD_READ: